Phillip and his family arrived in Curacao late in 1939—his father received a job offer from Dutch Shell to work on an oil refinery during World War II. The book says,

My mother, I knew, had not wanted to come to Curacao in late 1939, but my father had argued that he was needed for the war effort even though the United States was not at war then. (chapter 1)

Phillip’s mother had not wanted to come to the Dutch colony, but his father had pushed for the move because it was an excellent opportunity for him career-wise. Little had they known that the German U-boats would target the island. Living on the island became too dangerous, and so Phillip and his mother decided to return to Virginia.

Their small boat is torpedoed in April of 1942 after they have left Panama—this means that they spent just three years, all during the war, on the island of Curacao. Despite the danger and the fact that many ships were sunk in the weeks leading up to their departure, Phillip’s mother insisted they go back to Virginia and that they go by ship. The text tells us,

We were torpedoed at about three o'clock in the morning on April 6, 1942, two days after leaving Panama. (chapter 3)

The shooting of their small boat by a torpedo is what sets up the rest of the story. Phillip would not have been marooned on the cay if their ship hadn't been shot.

Phillip and his family lived in Curacao for a little bit less than three years.  I wish that I could be more specific than that, but the text is a bit vague on when Phillip and his family came to Curacao.  On page 15 (of my text), Phillip tells his readers that his family arrived on the island in "late 1939."  Due to the war, Phillip's family thinks that they will be safer back in the United States.  Phillip's father secures them passage in early April.  Unfortunately, the book doesn't give a year for that trip until the following chapter.  At the beginning of chapter three, Phillip tells his readers that the ship was torpedoed on April 6, 1942.  April of 1939 to April of 1942 would be three years on Curacao, but Phillip specifically said they arrived in late 1939.  I think Phillip lived in Curacao for two and a half years (give or take a month).